The problem in lifting over 2.5" without using a drop bracket lift, is your driveline, suspension, and steering angles. Your CV axles will be at a much greater angle, which will cause the rubber boots to touch each other, and they will eventually rub a hole in them. Then you have to replace the boot or if you leave it with a hole in them, dirt will get in there and ruin the joint. See this post if you dont beleive me

http://www.4x4wire.com/forums/showflat.php?Cat=0&Number=1167002

A diff drop kit from 4crawler will help with this angle.

Also, your tie rods will be at a weird angle and cause accelerated wear.

Your upper ball joint will be at a bad angle too if you go too high.

What are you trying to do with this truck? Look cool? Or actual offroad functionality?